The design of a shoe sole provides a shoe with a plethora of different properties and characteristics. An important property of the shoe that may be influenced by its sole is the bending stiffness. This is particularly important for a cycling shoe, such as a cycling shoe for road cycling, mountain biking, cyclocross, triathlon, downhill, etc.
A bicycle and its rider are propelled forward by the forces the rider transmits via his feet to the pedals of the bicycle. These forces are then further transmitted from the pedals through the crankset and the drivetrain system to drive the rear wheel of the bicycle. In order to facilitate an efficient transmission of the forces exerted by the rider from his feet to the pedals, a cycling shoe and, in particular, its sole should provide a high amount of bending stiffness. Otherwise, the sole might deform under the high forces exerted by the rider, leading to an undesirable energy loss and preventing the rider from making efficient use of his muscle power. Also, the foot of the rider and, in particular, the arch of the rider's foot may be more susceptible to injuries, e.g. by overstraining the arch of the foot, if the sole of the shoe does not offer sufficient support.
These aspects are not only relevant for cycling shoes, but concern other sports shoes as well, like those for field sports, running, football, basketball, American football, outdoor sport, etc. Also with these exemplarily mentioned kinds of sports it is very important to ensure a proper transmission of forces between the foot of a wearer and the ground, while at the same time providing support for the foot.
Soles of conventional cycling shoes, for example, therefore often contain sole plates made from, for example, a carbon fiber material to provide the desired stiffness to the sole. However, such carbon fiber plates increase the weight of the shoe if a high degree of stiffness is desired and also prevent sufficient ventilation of the foot. Moreover, they may be difficult to adapt to the anatomy of the sole of a rider's foot, such that a customization of the shoe sole, for example to avoid chaffing or pressure points, may not be possible or only be possible to a limited degree.
Recently, additive manufacturing methods, such as selective laser sintering, have been considered for providing customized three-dimensional objects. For example in the WO 2014/100462 A1 devices and methods for designing and manufacturing customized footwear are discussed. More specifically, the footwear may be customized for different athletic activities including cycling. This document also discloses that selective laser sintering could be used for the manufacture of the footwear.
Further documents discussing the use of additive manufacturing methods like laser sintering in relation to shoes are WO 2014/066172 A1, WO 2014/066173 A1, WO 2014/066174 A1 or WO 2014/008331 A2.
However, the sintered soles known from the prior art may have the disadvantage that they do not sufficiently take into account the anatomy of the feet of future wearers and may not be optimally geared towards the specific circumstances and requirements with respect to the desired direct transmission of forces from the feet of a rider to the pedals of a bicycle as discussed above.
It is therefore a problem underlying the present invention to provide improved soles for shoes, which at least partly overcome the above disadvantages. In particular, improved soles for cycling shoes are needed, that are light-weight and that allow sufficient ventilation and a customization to the anatomy of the feet of a wearer, while at the same time providing a sufficient bending stiffness and support to the feet of the wearer to ensure the desired direct transmission of forces from the feet to the pedals of a bicycle.